Rivera Studio Jake - No Output After Re-Cap

[Ascott]

Hi All. This is my second post to the forum, I posted some pics earlier on what a PITA it was to get the 4 Main power filter caps out they were glued down with black stuff that was really a pain to get them off, but i perservered, cleaned up the mess and put in the new caps. All seemed was going good until testing, Power on was fine. but volume increase resulted in nothing in either channel, you could barely hear some signal come through if it was cranked all the way up (only did this for a few seconds..) sounded basically about as loud as if it was coming through a headphone. It was built in 1997. I have used it and giggled with it off and on for about 15 years. It has all fresh tubes pre and power, bias set correctly fro some nice NOS EL34s. After having it out on the bench, there is a lot of burning around all the tube sockets, Ive cleaned it up quite a bit in the picture attached. Gave the whole board a cleaning, tube sockets were full of gunk,,,Checked cathode resistors, diodes all .5 on D1-D4, and some preliminary troubleshooting. Attached are schematics and pics...Just need a plan of attack on where to look. Sorry about the pic sizes...Rivera schematic_1.pdfRivera_schematic_2.pdfRivera_schematic_3.pdf

Not Sure if the input on V1 is bad, resistor value at least is correct.

Thanks again for any help...Would like to keep it going if I can...

-Scott

[nickb]

Are all the tubes lit up? What happens if you plug into the fx return? Check the supply voltages: -24,+24,-18,+18 Filament, +18 Logic, TP50, TP51 and the far side of R4. If that is OK, do a sanity check for the voltage on each plate.

[Ascott]

Thanks nickb,

I will try that next...

[Ascott]

All tubes are glowing including power tubes.
here is what I measured so far:

Test Point Expected VDC Measured VDC
V1 Grid TP1
V1 Plate TP2 (shared) 210 218
V2 Grid TP3
V2A Plate (TP4) to V3 305 334
V2A Plate (TP5) 205 225
V2B Plate (TP6) 200 218
V3B TP7
V3B Plate (TP8) 215 245
V3A Plate (TP9) 210 241
TP11 290
TP13 288
TP32 42
TP33 298
TP34 284
TP35 -41.66
TP36 -41.66
TP39 +28
TP40 -28
TP41 -41.66
V1 Pin 4 18
V2 Pin 4 6.96
V2 pin 5 -5,76
V2 pin 6 224
V3 pin 6 240
V3 pin 4 -5.76
V3 Pin 5 -18
TP50 428
TP51 456

[nickb]

Ooo very though You get a bonus point.

I don't see anything wrong there. What about the plugging in to the return jack test? Also carefully check the connections to the fx send/return board as something might be misplaced or loose.

[Chuck H]

Also...

I'm unclear about whether the amp was actually working before the power supply rebuild. If it was then IMHE the first thing to look for is errors in your work.

[Ascott]

HURRAY!!!!!!!

This is going to sound weird...but I just starting going through all the tone controls and when I turned up the bass control on Channel 2.....everything came to life!

Wow...not sure how that was limiting things.

[Enzo]

Did you also have the mid and treble controls at zero? Having all tone controls at zero results in no sound. Look at the schematic and see how it would ground off the signal path.

[Ascott]

doh....yep

Thanks you guys.